(1) Field of the Invention
The present invention relates to a CO.sub.2 laser machining apparatus.
(2) Description of the Prior Art
In general, CO.sub.2 laser beams are more useful than YAG (Yttrium-Antimony-Garnet) laser beams for machining processes such as printing (engraving), heat treatment, welding, cutting, drilling and the like bacause the former can attain an oscillation efficiency higher than the latter. As a result various machining apparatus, in which a CO.sub.2 laser oscillator is used as a light source, have been proposed and it has been intended to use them practically.
However, all of the known CO.sub.2 laser machining apparatus contain an optical system comprising a mirror and require a holder of said mirror, an arm supporting said holder and the like. As a result the construction of said optical system has been complicated and it has been unavoidable that the whole apparatus is large-sized.
For example, the machining apparatus is of such a type that said optical system is fixedly mounted and the stand for the objects to be machined is movable. The disadvantage is that a driving device of said stand is large-sized and thus the whole machining apparatus is a large-scale one.
On the other hand, where the machining apparatus of such a type is that the objects to be machined are fixedly mounted on the stand and laser beams travel toward said objects to be machined by rotating said mirror there is the disadvantage that said optical system is more complicated in structure, it being difficult to keep a high accuracy of said optical system. The irradiation angles of laser beams to said objects to be machined are varied with the transfer of said laser beams and consequently said objects to be machined are able to be vertically machined directly under a condenser while said objects to be machined are machined aslant at other positions, that is to say the states of machining are varied in dependence upon the positions of said objects to be machined.